Egg tart based on frozen egg yolk liquid and preparation method thereof

Abstract

The invention belongs to the technical field of food processing, and discloses an egg tart based on frozen yolk liquid and a preparation method of the egg tart. The preparation method comprises the following steps: adding polysaccharide and high-amylose corn starch into drinking water, and uniformly mixing to obtain polysaccharide-starch liquid; unfreezing the frozen egg yolk liquid, adding the polysaccharide-starch liquid, performing homogenization treatment, adding auxiliary materials, and performing uniform mixing so as to obtain egg tart liquid; and pouring the egg tart liquid into the egg tart skin for baking. According to the method, firstly, the gelatinization degree of protein of the frozen egg yolk liquid in the unfreezing process is reduced through ultrasonic-assisted water bath unfreezing treatment, and then under the combined action of polysaccharide, high amylose and homogenization treatment, the problem that many holes are formed in the egg tart due to gelatinization of the frozen egg yolk liquid is solved; meanwhile, the problem of egg tart surface focal spot aggregation caused by polysaccharide is solved. The egg tart based on the frozen egg yolk liquid is free of pores inside, smooth and compact in texture, fine and tender in taste, harmonious in egg and milk fragrance, dispersed in surface focal spots and good in overall quality.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to an egg tart based on frozen egg yolk liquid and a preparation method thereof. Background Art

[0002] Egg yolk liquid is the egg liquid obtained after fresh eggs are shelled and egg whites are separated. It is rich in nutrients such as protein, fat, minerals, vitamins, and has good emulsification and coloring functional properties. It is widely used in the preparation of baked foods such as egg tarts, bread, biscuits, and egg rolls. However, the rich nutrients make fresh egg yolk liquid susceptible to microbial contamination and difficult to store for a long time at room temperature. Freezing is a commonly used food storage and preservation technology. After the egg yolk liquid is frozen, not only can the shelf life be effectively extended, but its nutrients can also be retained to the maximum extent. However, after low-temperature freezing, the egg yolk liquid will have problems such as changes in microstructure, gelation, reduced fluidity and emulsification, resulting in a decrease in its application and processing performance and a decrease in the quality of the prepared products. Especially when used in the preparation of egg tarts, it will cause more pores to appear inside the egg tarts, which not only affects the taste of the food, but also makes the flavor substances that should be released slowly and continuously quickly and easily disperse, and the flavor layering and richness of the product are reduced. Summary of the invention

[0003] Based on the above reasons, the object of the present invention is to provide an egg tart based on frozen egg yolk liquid and a preparation method thereof, wherein the egg tart has no pores inside, has a smooth and firm texture, a delicate and tender taste, and a harmonious combination of egg and milk flavors, and has better edible quality.

[0004] In order to achieve the above object, the first technical solution adopted by the present invention is: The preparation method of egg tart based on frozen egg yolk liquid comprises: Adding polysaccharide and high-amylose corn starch into drinking water and mixing them evenly to obtain polysaccharide-starch liquid; Thawing the frozen egg yolk liquid, adding the polysaccharide-starch liquid and homogenizing, and then adding the auxiliary materials and mixing evenly to obtain the egg tart liquid; Pour the egg tart liquid into the tart crust and bake.

[0005] Furthermore, the method for thawing the frozen egg yolk liquid is: after ultrasonic treatment of the frozen egg yolk liquid, thawing in a water bath until the center temperature of the egg yolk liquid is 25-30°C.

[0006] Furthermore, the ultrasonic treatment has a power of 100-120 W, a frequency of 25-35 kHz, and a time of 3-5 min.

[0007] Furthermore, the temperature of the water bath is 20-25°C.

[0008] Furthermore, the mass fraction of the thawed egg yolk liquid in the egg tart liquid is 20%-25%.

[0009] Furthermore, the polysaccharide is sodium carboxymethyl cellulose.

[0010] Furthermore, the mass fraction of the polysaccharide in the egg tart liquid is 0.5‰-1.5‰.

[0011] Furthermore, the mass fraction of the high-amylose corn starch in the egg tart liquid is 0.8%-1.2%.

[0012] Furthermore, the homogenization pressure is 8-12 MPa.

[0013] The second technical solution adopted by the present invention is: The egg tart is prepared according to the aforementioned method for preparing an egg tart based on frozen egg yolk liquid.

[0014] The beneficial effects of the present invention are: The present invention firstly shortens the thawing time of frozen egg yolk liquid and reduces the gelation degree of protein in the frozen egg yolk liquid during the thawing process through ultrasonic-assisted water bath thawing treatment; then, under the joint action of polysaccharide, high-amylose corn starch and homogenization treatment, solves the problem of many holes generated inside the egg tart due to the gelation of the frozen egg yolk liquid, and solves the problem of scorch spot aggregation on the surface of the egg tart caused by polysaccharide.

[0015] The egg tart based on the frozen egg yolk liquid has no pores inside, no uneven roughness, smooth and firm texture, delicate and tender taste, harmonious egg and milk fragrance, scattered burnt spots on the surface, and better overall quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The egg tart cross-sections of Examples 1-3 and Comparative Examples 1-3, 5-7, and 9; Figure 2 Surface images of egg tarts of Examples 1-3 and Comparative Examples 1-3, 5-7, and 9. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present invention clearer, the scheme of the present invention is further described in detail below in conjunction with embodiment.It will be appreciated by those skilled in the art that the following examples are exemplary only, and are not intended to limit the scope of the present invention.In addition, in the following description, those not indicating specific conditions in the examples are carried out according to the conditions of normal conditions or manufacturer's recommendations.Reagents used or instruments not indicating manufacturers are conventional products that can be obtained by commercial purchase.

[0018] Freezing fresh egg yolk liquid can extend the shelf life of the egg yolk liquid and retain its nutrients to the maximum extent. However, the egg yolk liquid will undergo a certain degree of gelation during the freezing and thawing process, which will reduce its fluidity, emulsification and other properties. If the frozen egg yolk liquid is naturally thawed at room temperature and then directly mixed with other auxiliary materials, poured into the egg tart crust and baked, the resulting egg tart will have more pores inside, and the taste will be loose and have an uneven and rough feeling.

[0019] In view of the above problems, a first embodiment of the present invention provides a method for preparing an egg tart based on frozen egg yolk liquid, comprising: Adding polysaccharide and high-amylose corn starch into drinking water and mixing them evenly to obtain polysaccharide-starch liquid; Thawing the frozen egg yolk liquid, adding the polysaccharide-starch liquid and homogenizing, and then adding the auxiliary materials and mixing evenly to obtain the egg tart liquid; Pour the egg tart liquid into the tart crust and bake.

[0020] In this embodiment, the method for thawing the frozen egg yolk liquid is: after ultrasonic treatment of the frozen egg yolk liquid, thawing in a water bath until the center temperature of the egg yolk liquid is 25-30° C. Compared with the traditional natural thawing treatment at room temperature (the thawing time of 1 kg of frozen egg yolk liquid is about 4 hours), the ultrasonic-assisted water bath thawing treatment can significantly shorten the thawing time of the frozen egg yolk liquid and reduce the degree of gelation of the protein in the frozen egg yolk liquid during the thawing process.

[0021] The ultrasonic treatment has a power of 100-120 W, a frequency of 25-35 kHz, and a time of 3-5 min.

[0022] The temperature of the water bath is 20-25°C, and 1 kg of frozen egg yolk liquid is thawed in a water bath at this temperature for 25-30 min after the aforementioned ultrasonic treatment, and the center temperature can reach 25-30°C. It should be noted that if the mass of the frozen egg yolk liquid exceeds 1 kg, the thawing time in the water bath will be extended, but even if the mass of the frozen egg yolk liquid is 5 kg, the thawing time in the water bath will not exceed 45 min, and the quality of the thawed egg yolk liquid is close to the quality of the thawed 1 kg frozen egg yolk liquid.

[0023] It should be noted that the polysaccharide can be a common polysaccharide with a thickening effect, and its role is to cooperate with ultrasound-assisted water bath thawing and homogenization treatment to improve the emulsification stability of the egg yolk liquid, so that the composition of the egg yolk liquid is uniform during the processing, and no obvious particles and bubbles are generated, so as to ensure that no pores are generated inside the prepared egg tart. However, the applicant found that the use of polysaccharides will cause a new problem of scorched spots on the surface of the egg tart. Based on this problem, the present embodiment further introduces high-amylose corn starch, and the polysaccharide and high-amylose corn starch are added to the thawed egg yolk liquid and homogenized, which solves the problem of pores inside the egg tart and the problem of scorched spots on the surface of the egg tart caused by the polysaccharide. In this embodiment, the polysaccharide is sodium carboxymethyl cellulose, specifically high-viscosity sodium carboxymethyl cellulose with a viscosity of 2500-2750 mPa.S. The polysaccharide will not affect the flavor and taste of the egg tart, and the mass fraction of the polysaccharide in the egg tart liquid is 0.5‰-1.5‰. It should be noted that if the mass fraction of polysaccharides is lower than 0.5‰, pores will still appear inside the egg tart. If it is higher than 1.5‰, the viscosity of the egg yolk liquid will be too high, causing excessive expansion during the subsequent baking process, which will cause the inside of the egg tart to collapse.

[0024] In this embodiment, the mass fraction of the high-amylose corn starch in the egg tart liquid is 0.8%-1.2%. It should be noted that if ordinary corn starch with an amylose content of 20%-30% is used, the problem of focal spot aggregation on the surface of the egg tart cannot be solved. If the mass fraction of the high-amylose corn starch is lower than 0.8%, the problem of focal spot aggregation on the surface of the egg tart cannot be solved; if it is higher than 1.2%, the subsequently prepared egg tart liquid will have obvious precipitation and cannot be further used to prepare egg tarts. In this embodiment, the mass fraction of the thawed egg yolk liquid in the egg tart liquid is 20%-25%, and the mass fraction of drinking water in the egg tart liquid is 25%-35%.

[0025] In this embodiment, the homogenization pressure is 8-12 MPa, and the number of homogenization times can be conventionally adjusted according to the mixing conditions of the materials, for example, the number of homogenization times is 1-3 times.

[0026] It should be noted that the types and addition amounts of the auxiliary materials can be conventionally selected by those skilled in the art according to the requirements for the taste of the egg tarts, and are not particularly limited in this embodiment.

[0027] In this embodiment, the auxiliary materials include milk, sugar, cream, and whole milk powder, and the mass fractions of the milk, sugar, cream, and whole milk powder in the egg tart liquid are 18%-22%, 7%-9%, 10%-12%, and 6%-8%, respectively.

[0028] It should be noted that the baking temperature and time can be routinely adjusted by those skilled in the art according to the selected baking equipment and actual experience, and are not particularly limited in this embodiment. For example, when baking in an electric oven, the upper tube temperature is 190-210°C, the lower tube temperature is 210-230°C, and the time is 20-25 minutes; when baking in a convection oven, the temperature is 175-190°C, and the time is 20-25 minutes.

[0029] Specific embodiments for implementing the present invention will be disclosed below, as well as corresponding comparative examples to demonstrate the relevant technical effects of the present invention.

[0030] The frozen egg yolk liquid in the following examples all comes from Mianyang Luanxiang Fengji Food Co., Ltd.

[0031] Example 1 To prepare the frozen egg yolk based tart: The egg tart liquid includes, by weight, 20% thawed egg yolk liquid, 0.5‰ high-viscosity sodium carboxymethyl cellulose (viscosity 2500 mPa.S), 0.8% high-amylose corn starch, 18% milk, 7% white sugar, 12% cream, 8% whole milk powder, and the rest is drinking water; Adding high-viscosity sodium carboxymethyl cellulose and polysaccharide into drinking water and mixing them evenly to obtain polysaccharide-starch liquid; 1 kg of frozen egg yolk liquid was ultrasonically treated at a power of 100 W and a frequency of 25 kHz for 3 min, and then thawed in a water bath at 25 ℃ until the center temperature of the egg yolk liquid reached 30 ℃ to obtain thawed egg yolk liquid; Adding polysaccharide-starch liquid to the thawed egg yolk liquid, homogenizing once at a pressure of 8 MPa to obtain pretreated egg yolk liquid; The pretreated egg yolk liquid, milk, white sugar, cream and whole milk powder are mixed evenly to obtain egg tart liquid; The egg tart liquid was placed in an electric oven and baked at an upper tube temperature of 190°C and a lower tube temperature of 210°C for 20 min to obtain an egg tart based on frozen egg yolk liquid.

[0032] Example 2 Preparation of egg tarts To prepare the frozen egg yolk based tart: The egg tart liquid includes, by weight, 100% of the following: 23% of thawed egg yolk liquid, 1‰ of high-viscosity sodium carboxymethyl cellulose (viscosity 2650 mPa.S), 1% of high-amylose corn starch, 20% of milk, 8% of white sugar, 11% of cream, 7% of whole milk powder, and the rest is drinking water; High-viscosity sodium carboxymethyl cellulose and polysaccharide were added to drinking water and mixed evenly to obtain polysaccharide-starch liquid; 3 kg of frozen egg yolk liquid was ultrasonically treated at a power of 110 W and a frequency of 30 kHz for 4 min, and then thawed in a water bath at 22 ℃ until the center temperature of the egg yolk liquid reached 27 ℃ to obtain thawed egg yolk liquid; Adding polysaccharide-starch liquid to the thawed egg yolk liquid, homogenizing twice at a pressure of 10 MPa to obtain pretreated egg yolk liquid; The pretreated egg yolk liquid, milk, white sugar, cream and whole milk powder are mixed evenly to obtain egg tart liquid; The egg tart liquid was placed in an electric oven and baked for 25 min at an upper tube temperature of 210 °C and a lower tube temperature of 230 °C to obtain an egg tart based on frozen egg yolk liquid.

[0033] Example 3 Preparation of egg tarts To prepare the frozen egg yolk based tart: The egg tart liquid includes, by weight, 100% of the following: 25% of thawed egg yolk liquid, 1.5‰ of high-viscosity sodium carboxymethyl cellulose (viscosity 2750 mPa.S), 1.2% of high-amylose corn starch, 22% of milk, 9% of white sugar, 10% of cream, 6% of whole milk powder, and the rest is drinking water; Adding high-viscosity sodium carboxymethyl cellulose and polysaccharide into drinking water and mixing them evenly to obtain polysaccharide-starch liquid; 5 kg of frozen egg yolk liquid was ultrasonically treated at a power of 120 W and a frequency of 35 kHz for 5 min, and then thawed in a water bath at 20 ℃ until the center temperature of the egg yolk liquid reached 25 ℃ to obtain thawed egg yolk liquid; Adding polysaccharide-starch solution to the thawed egg yolk solution, homogenizing for 3 times under a pressure of 12 MPa to obtain the pretreated egg yolk solution; The pretreated egg yolk liquid, milk, white sugar, cream and whole milk powder are mixed evenly to obtain egg tart liquid; The egg tart liquid was placed in a convection oven and baked at 180°C for 22 min to obtain an egg tart based on frozen egg yolk liquid.

[0034] Comparative Example 1 The difference from Example 1 is that the thawing method of the frozen egg yolk liquid is natural thawing at room temperature.

[0035] Comparative Example 2 The difference from Example 1 is that the ultrasonic treatment is omitted and the frozen egg yolk liquid is directly thawed in a water bath at 25°C.

[0036] Comparative Example 3 The difference from Example 1 is that the power of ultrasonic treatment is 90 W.

[0037] Comparative Example 4 The difference from Example 1 is that the power of ultrasonic treatment is 130 W.

[0038] Comparative Example 5 The difference from Example 1 is that the mass fraction of high-viscosity sodium carboxymethyl cellulose is 0.3‰.

[0039] Comparative Example 6 The difference from Example 1 is that the mass fraction of high-viscosity sodium carboxymethyl cellulose is 1.7‰.

[0040] Comparative Example 7 The difference from Example 1 is that the mass fraction of high-amylose corn starch is 0.6%.

[0041] Comparative Example 8 The difference from Example 1 is that the mass fraction of high-amylose corn starch is 1.4%.

[0042] Comparative Example 9 The difference from Example 1 is that the high-amylose corn starch is replaced by ordinary corn starch (amylose content is 30%).

[0043] In Comparative Example 4, due to the excessive ultrasonic power, the fat globules in the egg yolk liquid were broken, the protein was denatured, and the egg yolk liquid showed oil-water separation, which was not suitable for further preparation of egg tarts; in Comparative Example 8, after increasing the amount of high-amylose corn starch added, the obtained egg tart liquid showed obvious precipitation and could not be further used for preparation of egg tarts, so there were no relevant test results of Comparative Examples 4 and 8 in the subsequent test examples.

[0044] Test Example 1: Test of internal pores in egg tarts The egg tarts of Examples 1-3 and Comparative Examples 1-3, 5-7, and 9 were cut open to observe the pores inside the samples of each group.

[0045] Figure 1 The egg tart cross-sections of Examples 1-3 and Comparative Examples 1-3, 5-7, and 9 are shown in FIG. Figure 1 It can be seen that there are no obvious pores inside the egg tart samples of Examples 1-3 and Comparative Examples 6, 7, and 9, the egg tart of Comparative Example 6 has obvious internal collapse, and there are more holes inside the samples of Comparative Examples 1-3 and 5.

[0046] Test Example 2: Spot dispersion test on egg tart surface The focus aggregation on the surfaces of the egg tart samples of Examples 1-3 and Comparative Examples 1-3, 5-7, and 9 was observed.

[0047] The surface images of each group of samples are shown in Figure 2As shown in the figure, it can be seen that there are multiple small focal spots scattered on the surface of the egg tarts of Examples 1-3 and Comparative Examples 1-3, 5, and 6, while there is only one large focal spot on the surface of the samples of Comparative Examples 7 and 9, and the focal spots are obviously concentrated.

[0048] Test Example 3 Sensory Evaluation An evaluation panel consisting of 10 trained sensory assessors (5 males and 5 females) conducted a sensory evaluation on the egg tart samples of the embodiment and the comparative example. The overall color of the egg tart and the accumulation of burnt spots on the surface were observed. The egg tarts were then cut open to observe the formation of internal pores. Finally, the samples were tasted and sensory scores were given for each group of samples. The scoring criteria are shown in Table 1, and the scoring results are shown in Table 2.

[0049] Table 1 Sensory scoring standard for egg tarts based on frozen egg yolk liquid .

[0050] Table 2 Sensory evaluation results of egg tart samples of the embodiment and comparative example .

[0051] According to the sensory scoring results in Table 2, the sensory scores of the egg tart samples of Examples 1-3 are all above 95 points, indicating that the overall edible quality of the egg tarts prepared by the process of the present invention is better. Compared with Example 1, the scores of each index of the egg tart samples of each comparative example have decreased to a certain extent, and the sensory quality is poor.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an egg tart based on frozen egg yolk liquid, characterized in that: include: Adding polysaccharide and high-amylose corn starch into drinking water and mixing them evenly to obtain polysaccharide-starch liquid; Thawing the frozen egg yolk liquid, adding the polysaccharide-starch liquid and homogenizing, and then adding the auxiliary materials and mixing evenly to obtain the egg tart liquid; Pour the egg tart liquid into the tart crust and bake.

2. The preparation method according to claim 1, characterized in that The method for thawing the frozen egg yolk liquid is as follows: after ultrasonic treatment of the frozen egg yolk liquid, thawing in a water bath until the center temperature of the egg yolk liquid is 25-30°C.

3. The preparation method according to claim 2, characterized in that: The ultrasonic treatment has a power of 100-120 W, a frequency of 25-35 kHz, and a time of 3-5 min.

4. The preparation method according to claim 2, characterized in that: The temperature of the water bath is 20-25°C.

5. The preparation method according to claim 1, characterized in that: The mass fraction of the thawed egg yolk liquid in the egg tart liquid is 20%-25%.

6. The preparation method according to claim 1, characterized in that: The polysaccharide is sodium carboxymethyl cellulose.

7. The preparation method according to claim 1, characterized in that: The mass fraction of the polysaccharide in the egg tart liquid is 0.5‰-1.5‰.

8. The preparation method according to claim 1, characterized in that: The mass fraction of the high-amylose corn starch in the egg tart liquid is 0.8%-1.2%.

9. The preparation method according to claim 1, characterized in that: The homogenization pressure is 8-12 MPa.

10. An egg tart prepared by the method for preparing an egg tart based on frozen egg yolk liquid as claimed in any one of claims 1 to 9.

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